Safety protective device



Feb. 4, 1964 R. E. FARlsH, JR 3,120,414

SAFETY PROTECTIVE DEVICE Filed Feb. 17, 1961 IN VEN TOR /aferf//s/Z JE BY m me@ ATTORNEYS United States Patent O 3,120,414 SAFETY PROTECTIVE DIWCE Robert E. Parish, Ir., 321 14th St., 17.0. Rox 207, Columbus, Ga. Filed Feb. 17, 1961, Ser. No. 90,071 I Claim. (Qi. 339-14) This invention relates to a safety protective device and has particular applicability to a safety means for grounding an electrical accessory connected by a flexible cord to an outlet receptacle. The instant invention comprises an improvement over my previous Fatent No. 2,749,381, dated lune 5, 1956, entitled Safety Protective Device.

A primary object of the invention is the provision of an improved means for grounding an electrical cord ex tending from an electrical accessory so as to eliminate the possibility of tire or hazard to life by shock in the event that a short circuit should occur.

An additional object of the invention is the provision of such au improved grounding means which is carried by the cover or escutcheon plate of an outlet box in combination with a grounding contact carried by the plug of the electrical accessory cord.

A further object of the invention is the provision of such a protective device which may be advantageously employed with a conventional electrical outlet, or a standard outlet including auxiliary grounding means, and which may be employed with a plastic or similar nonconductive plate.

A further specific object of the invention is the provision of an electrical plug for use with such a cover plate and outlet wherein the electrically conductive prongs of the plug and the grounding prong are in substantial longitudinal alignment, thus permitting the plug to be inserted in relatively narrow or constricted localities.

A further obglect of the invention is the provision of a device of this character which is sturdy and durable in construction, reliable and ecient in operation, and relatively simple and inexpensive to manufacture and utilize.

Still other objects reside in the combinations of elements, arrangements of parts, and features of construction, all as will be more fully pointed out hereinafter, and disclosed in the accompanying drawing wherein there are shown preferred embodiments of this inventive concept.

In the drawing:

FIGURE l is a front elevational view of a cover plate of plastic or similar non-conductive material employed to cover an electrical outlet box, certain concealed portions thereof being indicated in dotted lines.

FIGURE 2 is a sectional view taken substantially along the line 2 2 of FIG. 1 as viewed in the direction indicated by the arrows.

FIGURE 3 is a side elevational View of a plug adapted to be used with the cover plate of FIG. l, certain concealed parts being indicated in dotted lines; and

FIGURE 4 is an end elevational view of the plug oi FIG. 3 as viewed from the bottom.

Similar reference characters refer to similar parts throughout the several views of the drawing.

Having reference now to the drawings in detail, there is disclosed at 1l) a cover plate, constructed ot plastic or similar non-conductive material which is adapted to be attached to a conventional electrical outlet box shown in dotted lines at 11, the latter being provided with inwardly extending lugs or ears 12 having threaded bores for the reception of holding screws 13 for the cover plate. The box is constructed of metal in the usual manner and suitably grounded.

The underside of plate 1i) is provided with resilient lCe lug members 14- Which are adapted to retain a U-shaped metallic conductive strip 15, the latter being in electrical association with the screws 13 and the lugs or ears 12, to serve as a ground. Plate 1l) is provided with socket openings 16 for the reception of the prongs of an electrical plug connected to a cord in the usual manner. A socket 17 is shown 011 the left side of FIG. 1 of conventional type having simply the two openings 16, while for the sake of illustration, a second socket 18 of the so-called standard type is shown on the right side having the usual opening 19 therein for a ground contact carried by the plug.

The plate also carries a pair of openings 2li, one in alignment with each pair of openings 16, the latter being adapted for the ground prong or member of a particular plug comprising a portion of the instant invention.

Underlying each opening 211 is a U-shaped conductive strip 21 having the openings 21a in alignment therewith, having ears 22 at its upper end, the latter being spot welded or otherwise suitably secured in electrical association with the underside of strip 1S. A pair of spring arms 23 are secured as by means of a rivet 24 or the like interiorly of the Ushaped members 21, and are adapted to receive a ground member in a manner to be more fully described hereinafter.

A cardboard cup 25 is positioned around each U-shaped conductive member 21 for the purpose of preventing electrical contact thereof with any part of the box 11.

While the cup has been described as being made of cardboard, it will be understood that any other desired material having insulating characteristics may be employed, if desired.

FIGURES 4 and 5 disclose a plug generally indicated at 3Q which is comprised of rubber, plastic, or other insulating material, and which is provided with a body 31 from the underside of which depend a pair of electrically conductive prongs 32 which are adapted to be inserted in the openings 16 of either a standard or conventional socket. A ground member 33 is also provided in alignment with the prongs 32, the latter being substantially U-shaped in configuration, as best shown in FIG. 5, and adapted to engage through the associated hole Ztl to be contacted by the spring ngers 23. It is to be noted that the member 33 is longer than the prongs 32 so that ground is established before any electrical circuit is established. A ground wire 34 extends from ground contact member 33 interiorly of a cable 35, while conductive wires 36 similarly extend from prongs 32 for the establishment of the electrical circuit.

It will thus be seen that by virtue of the aligned contact prongs and the ground member of the plug Sil, and the positioning of openings Zt) in alignment with the opening 16 of the cover plate, that a plug may be used in a relatively small or confined space, and that such a plug provides complete safety in the event of short circuits, in that a ground is established through the spring fingers 23, U-shaped strip 21, ears 22, plate 15, lugs 12, and outlet receptacle 11.

From the foregoing it will now be seen that there is herein provided an improved safety protective device which accomplishes all the objects of this invention, and others, including many advantages of great practical utility and commercial importance.

As many embodiments may be made of this inventive concept, and as many modifications may be made in the embodiment hereinbefore shown and described, it is to be understood that all matter herein is to be interpreted merely as illustrative, and not in a limiting sense.

I claim:

In combination with an electrical outlet box having at least one socket, said socket comprising electrical plug passages disposed in substantially parallel relationa ship with respect to one another and extending in a generally longitudinal direction of said outlet box, a protective safety device universally usable with said electrical outlet box and the electrical circuits thereof comprising a non-conductive cover plate of generally rectangular configuration particularly adapted to be positioned upon and with respect to said outlet box, means for securing said cover plate to said box and being positioned oppositely of said sockets, an electrically conductive strip of generally U-sha'ped contiguration positioned llatly upon and secured With respect to the underside of said cover plate, the legs of said strip being positioned in underlying relationship With respect to said securing means, said strip having spaced openings extending therethrough in alignment with said plug passages, said cover plate having openings extending therethrough positioned in alignment with the openings extending through said strip, electrically conductive socket members positioned upon and secured with respect to said strip in underlying relationship with respect thereto and in electrically conductive relationship therewith, said socket members being positioned upon and with respect to said strip in alignment with the openings extending therethrough, and eleci trically conductive spring fingers positioned with said socket members, whereby at least one electrical plug having an insulated body and a grounding plug longitudinally axially aligned With a pair of substantially parallel electrically conductive prongs is particularly adapted to be mutually cooperatively engageable with the sockets of said outlet `eox and grounded by insertion of the grounding plug thereof Within and with respect to the spring lingers of said socket members.

References Cited in the file of this patent UNITED STATES PATENTS 1,602,370 Avery Oct. 5, 1926 1,645,950 Hines Oct. 18, 1927 1,927,245 Russell Sept. 19, 1933 2,579,538 Bierce Dec. 25, 1951 2,749,381 Farish June 5, 1956 FOREIGN PATENTS $30,349 Germany Sept. 15, 1955 935,616 Germany NOV. 24, 1955 692,143 Great Britain May 27, 1953 

